Numerous surgical procedures, such as coronary bypass surgery, reverse or in-situ femoral-popliteal or femoral-tibial bypass procedures and the like, may involve accessing and/or harvesting the saphenous vein or other blood vessel of a patient. For example, in coronary bypass surgery, a vein may be harvested from elsewhere in the patient's body and grafted into place between the aorta and a coronary artery. It is generally preferred to use a vein taken from the patient undergoing the surgery, as the patient is a ready source of suitable veins that will not be rejected by the body after grafting. In particular, the saphenous vein in the leg is often used for this procedure, for example, because the saphenous vein is typically 3-5 mm in diameter and comparable in size to the coronary arteries. Furthermore, the venous system of the leg is sufficiently redundant that the saphenous vein may be removed and the remaining veins in the leg will continue to provide adequate return blood flow. Alternatively, the cephalic vein in the arm may sometimes be used.
Traditionally, to harvest the saphenous vein, an open surgical procedure has been used to expose and remove the vein from the leg. Because of wound morbidity and patient pain often encountered in such procedures, however, minimally invasive access has become increasingly preferred.
For example, instead of an open procedure, an interrupted incision method may be used in which a series of incisions with skin bridges between them are made between the groin, the knee and/or the ankle. Through the incisions, the surgeon dissects the vein from the surrounding tissues, lifts the vein from the tissues, and divides and ligates the various tributary veins that feed into the saphenous vein. Once the vein is completely mobilized, the surgeon cuts the ends of the vein and removes it from the leg. The incisions in the leg are closed, and the vein is prepared for implantation.
During an interrupted incision procedure, a retractor may be used to assist in visualization of the vein. The retractor typically includes a wide, flat shaft with a handle on its proximal end made from stainless steel. The retractor may be inserted into an incision and directed along a previously dissected path over a section of vein to be harvested. The handle of the retractor may then be lifted away from the surface of the leg, thereby maintaining the space created by dissection under the shaft adjacent the vein in an open condition. Such retractors may include a source of light connected to the proximal end, and light from the light source may be projected into the space to facilitate visualization of the vein.
In an alternative method, vein harvesting may be accomplished using an endoscopic procedure. One or more small incisions may be made at selected locations for providing access to the vein being harvested. For example, to harvest the saphenous vein, an incision may be made at the groin, at the knee, and/or at the ankle. A tunneling instrument, such as a blunt or soft-tipped dissector, may be utilized to dissect subcutaneous tissue along the anterior surface of the vein being harvested. Such instruments generally include an elongate member, which can be fabricated from transparent, opaque or other material, having a rounded distal end and a passage therein for receiving an endoscope, the endoscope providing visualization within or beyond the walls of the instrument.
The tunneling instrument is inserted into the incision and advanced or pushed along between tissue layers to dissect and expose the saphenous vein. The tip of the instrument is generally kept near or in contact with the vein as the instrument is advanced along, thereby creating a small tunnel adjacent the anterior surface of the vein. An inflatable balloon (alternatively provided in a collapsed condition on the tunneling instrument prior to insertion into the incision) may be introduced into the tunnel, and inflated to further dissect the tunnel to an appropriate size for surgery.
Once the desired length of vein is exposed and an appropriate tunnel developed, the balloon and/or tunneling instrument may be removed, and a retractor, typically a wide flat shaft with a handle on its proximal end, may be inserted into the incision and directed along the dissected path over the section of vein to be harvested. The handle of the retractor may then be lifted away from the surface of the leg, thereby maintaining the working space created by dissection under the shaft adjacent the vein in an open condition. Surgical instruments may then be inserted into the working space to dissect the tissues surrounding the vein, ligate tributary veins, and mobilize the vein. An endoscope may be provided in a passage in the retractor or inserted directly into the working space to allow visualization during the harvesting procedure.
Retractor devices in vein harvesting procedures often have limitations. For example, such retractors typically require external support to hold the retractor away from the surface of the vein and maintain the working space. The surgeon or physician's assistant may have to hold a handle on the retractor, preventing both hands from being free for the procedure or may even require an assistant. Alternatively, an external mechanical support may be provided to hold the retractor, but such a support may interfere with access to the operative site.
Some retractors include a distal hood capable of maintaining a working space thereunder. These hoods, however, only create a limited self-supported working space, requiring that the retractor be moved when it is desired to work in a new location. Such retractors also generally require external support to provide access along the retractor shaft between the incision and the hooded space.
Accordingly, there is a need for a device for retracting subcutaneous tissues and/or for holding open a working space during surgical procedures that provides improved illumination and/or visualization within the space.